The present invention relates to the production of alumina and, more particularly, to the production and recovery of alumina from the vapor phase reaction between steam and an aluminum alkoxide.
It is known to produce alumina by contacting an aluminum alkoxide with water in a liquid phase reaction according to the following equation: EQU Al(OR).sub.3 +2H.sub.2 O.fwdarw.1/2(Al.sub.2 O.sub.3)+3ROH
The reaction is normally carried out in a large excess of water so that an aqueous slurry containing roughly 12% Al.sub.2 O.sub.3 is formed. The alcohols formed in the hydrolysis separate as a separate liquid phase and are removed by decanting the bulk phase and then steam stripping the aqueous slurry to remove dissolved alcohols. The alumina is then recovered by flash drying the slurry in a spray dryer or other similar drying apparatus. Since there is a relatively large quantity of excess water used in the process to maintain the alumina in a slurry form, the spray drying process adds significant energy costs to the process.
U.S. Pat. No. 2,579,251 disclose the preparation of alumina by admixing aluminum alkoxide vapors with steam to hydrolyze the aluminum alkoxides suspended therein. However, in the process disclosed in the patent, the aluminum alkoxide is initially prepared in vapor form in advance of its reaction with the gaseous steam. This adds significantly to the complexity and energy costs of the overall reaction to produce alumina.